Spin Hall effect transistor


60 years after the discovery of a transistor its operation is still based on the same physical principle of electrical manipulation and detection of electron’s charge in a semiconductor. Since we are quickly approaching the ultimate down-scaling limit it is now an eminent task to establish new physical principles of transistor operation. One extensively studied possibility is utilizing the second basic attribute of electron which is its spin. Theoretical proposal of electrical manipulation and detection of electron’s spin in semiconductors is 20 years old. However, its experimental realization turned out to be unexpectedly difficult. The FZU based team has engaged recently discovered quantum-relativistic phenomena for both spin manipulation and detection to realize the spin transistor and to demonstrate spin-logic operation. FZU was responsible for the work concept, experiments, theory.


(A) Schematics of the measurement setup with optically injected spin-polarized electrical current propagating through the Hall bar and corresponding experimental Hall effect signals at crosses H1 and H2. The Hall resistances, RH = VH/IPH, for the two opposite helicities of the incident light are plotted as a function of the focused (∼1 μm) light spot position, i.e., of the position of the injection point. Increasing x corresponds to shifting the spot further away from the Hall detectors. (B) Same as (A) for measurement geometry in which electrical current is closed before the first detecting Hall cross H1. (C) Schematics of the diffusive transport of injected spin-polarized electrons and Monte-Carlo simulations of the out-of-plane component of the spin of injected electrons.